Theoretical analysis applied game theory model and correlate analysis to verify conclusions about the influence of its variation on industrial concentration and product differentiation . conclusions of this paper : nominal tariff rates show negative correlations with industrial concentration whereas non - tariff barriers show positive correlations ; increase of non - tariff barriers will enlarge the differences between imported and native goods in a short period and the mentioned differences may be erased by technological advance made by import nations in a long time 最终结论：名义关税税率变动与产业集中度变动呈现负相关关系；非关税壁垒变动与产业集中度变动呈现正相关关系；非关税壁垒的增高会在短期内加大进口品与国产品的差异程度；如果长期内非关税壁垒不发生变化，差异程度将趋于消失，消失的过程表现为出口国对技术壁垒的跨越和产品差异与国外的趋同。
